Hydraulic valves for cam phasers for internal combustion engines are well known. The hydraulic valve includes a piston that is axially movable in a housing of a hydraulic valve and controls a hydraulic loading of the cam phaser. Hydraulic valves come in different configurations. The housing is configured hollow cylindrical. The piston is also configured hollow cylindrical. Controlling the cam phaser is performed hydraulically according to a position of a flowable piston and a corresponding opening or closing of connections configured at the housing.
The publication documents DE 10 2013 104 573 A1 and DE 10 2013 104 575 A1 disclose a hydraulic valve which includes a supply connection at a housing end so that a direct flow exposure of the piston received in the housing and thus a straight line loading of the piston with hydraulic fluid supplied through the supply connection is facilitated. The piston has a complex external geometry so that a back flowing into the piston from the operating connections is avoided.
From the publication documents US 2014/0311333 A1 and US 2014/0311594 A1 a hydraulic valve is known which includes check valves that are configured at a circumference of the piston. This requires either a complex housing configuration for receiving and securing the check valves or the housing is configured in several components and requires complex assembly. The piston is configured in plural components and the individual components have to be joined concentrical which requires complex assembly in order to prevent axial misalignment when the components are pressed together.
Another hydraulic valves which includes two respective connection openings for each consumer connection is disclosed in the patent document U.S. Pat. No. 8,662,040 B2. Due to a high number of connection openings the hydraulic valve is rather long.